Idling Issues

[Icefyre]

Howz it goin everybody? I'm kinda new to this (obviously), but you gotta start somewhere... I recently purchased a 91 Accord. The previous owner warned me of a 'rough' idle. The car was $50 so I figured what the hey... I've received many opinions since as to how to fix it, from all my friends and coworkers, none of whom are actual mechanics and are just as much a weekend warrior as I am, so I'd like to see what other thoughts there are on this:

Problem: Idles immediately after start by revving to 3,000 then dropping to 1,000 - It will continue this bounce, even when I've come to a stop at a traffic light. When the vehicle is in motion it 'disappears', until I slow to idle speed.

Diagnostic 'OPINIONS':
1. Possible vacuum leak
2. Possible clogged fuel injector(s)
3. Possible problems with Mass Airflow Sensor

Can anyone confirm/deny/or better yet suggest any opinion on this matter? Greatly Appreciated

[maxspeedhonda]

Those are all possiblities, I had a similair problem twice. Once it was a vaccum leak and then the idle control valve. Check your vaccum hoses, it's easy to do and will only take a minute, let us know if that doesn't help.

[ryanryan]

you have almost the same problem that i have

first use a carb cleaner spraycan, start engine and spray around vaccum hose to and see if engine stablize

question : your car is carburated not fuel injected right

[Icefyre]

My bad!!

Yes it is fuel injected. I'll try the carb cleaner tho, an I plan on runnin a complete fuel system cleaner through fer good measure. If neither of those work, I guess I'm off to purchase a book, so I can locate the mass airflow sensor, and then maybe the idol control valve...I guess it's jus gonna be lotz of trial and error...the car runs well other than that annoyance...thanx

[accordztech]

there is no Mass air flow sensor in the car, just a stupid sensor. check that iAC valve thats is ur best bet. tune up the car timming and stuff since its a ruff ride. i never had this problem wiht my car. it can be a vacumn line too...buy the book u will be saved.

[Icefyre]

Well I've bought a book, and needless to say your advice has was on the money...Thank you. I'll let you all know any further developments. Now I seem to have stumbled upon some other issues though. (hehehe) What should I expect for $50 huh?

[bx10466]

ok, my problen isn't the idle bouncing, it goes down to like 500 rpm. It only does this in drive, cause if I put it in neutral the rpm's go up to normal... Hope you can help me?

[accordztech]

o man thats normal for the idle to drop but thats a little low, mine drops to 700 around there. just raise your idle with the idle adjustment screw on the throttle body, its a black screw with a flat head. adjust it and reset the ecu and check it now and then. if the car idles too high normally then lower it a bit more.

[hondachic]

Reset the ECU. How do ya do that? The only ECU's I have ever reset were in Chevy's. Is it the same way. I have a 97 Honda though. I didn't think you had to reset the ECU's on anything 95 or up.

[aleksey]

change your thermostat. I just had the same problem & that was all there was to it. Now I have heat again & my idle doesn't jump up & down when in park. The part only costs $12 - try it & see where that takes you.

[the_mad_scientist]

Resetting the ECU is pretty easy. All you'd have to do, basically, is disconnect the negative battery cable and let it sit like that for about ten minutes. When you reconnect the cable, it will be reset . I think there's another way to do it, however.